Variation of the glycosaminoglycans of the intervertebral disc with ageing. II. Non-chondrodystrophoid breed.

The variation with age and spinal level of the glycosaminoglycan distribution in the greyhound (a non-chondrodystrophoid breed) intervertebral disc has been assessed by means of histochemical and chemical methods. The principal glycosaminoglycans of the greyhound disc are the chondroitin sulphates. With ageing, there is evidence of a decline in these components and the replacement by keratosulphate. The discs of this breed contain high proportions of sialic acid and hexosamines well into old age which are thought to be associated with non-collagenous proteins (glycoproteins). The maintenance of glycosaminoglycans and glycoprotein levels in the disc nucleus pulposus into old age is possibly associated with the relatively low incidence of disc disorders in the non-chondrodystrophoid breeds.